Security seal unit with optical fibre

ABSTRACT

The subject of the invention relates to an optical fibre sealing unit that contains a basic bundle consisting of light-transmitting fibres, a signalling bundle also consisting of light-transmitting fibres, a cable sheath and receiving bodies positioned at both ends of the cable sheath, the receiving bodies have an accepting space suitable for the fixing of at least some of the light-transmitting fibres and a transmitting body that allows light to pass through it, the basic bundle and the signalling bundle are arranged in the cable sheath and the one end and the other end of the basic bundle are each fixed in the accepting space of a receiving body in such a way so that they can not move, one end of the basic bundle is fitted to the transmitting body of one of the receiving bodies and the other end of the basic bundle is fitted to the transmitting body of the other receiving body.  
     The characteristic feature of the invention is that one end ( 21 ) of the signalling bundle ( 20 ) is fixed in the vicinity of the one end ( 11 ) of the basic bundle so as to prevent light input, while the other end ( 22 ) of the signalling bundle ( 20 ) is clamped into the light-transmitting output member ( 60 ) in the vicinity of the other end ( 12 ) of the basic bundle ( 10 ).

The subject of the invention relates to an optical fibre sealing unit that contains a basic bundle consisting of light-transmitting fibres, a signalling bundle also consisting of light-transmitting fibres, a cable sheath and receiving bodies positioned at both ends of the cable sheath, the receiving bodies have an accepting space suitable for the fixing of at least some of the light-transmitting fibres and a transmitting body that allows light to pass through it, the basic bundle and the signalling bundle are arranged in the cable sheath and the one end and the other end of the basic bundle are each fixed in the accepting space of a receiving body in such a way so that they can not move, one end of the basic bundle is fitted to the transmitting body of one of the receiving bodies and the other end of the basic bundle is fitted to the transmitting body of the other receiving body.

Different security sealing devices are widely used for the secure and monitored locking of the load area of transportation devices when goods are transported and for simply determining the unauthorised access to the transported products. Those devices can also be listed among these sealing devices that contain a lengthy sealing element threaded through loops on the wing doors or door of the loading area to be protected of transporting vehicles, e.g. trucks, or on the tarpaulin and on the frame delimiting this, which device is then clamped in a sealing structure. Numerous versions of these so-called “lead seals” have been used to this day.

There is a type of lead seal that consists of a lengthy sealing element, and a flexible signalling unit suitable for transmitting light made from optical fibres, in general glass fibres. There essence is that the regularly positioned fibres at the two ends of the signalling unit are mixed up in the intermediate part of the signalling unit. By selecting a suitable light source and positioning it at one end of the undamaged signalling unit the light travels unobstructed and with nearly the same intensity through the fibres and appears at the other end of the signalling unit. However, if the signalling unit is cut the unordered fibres are mixed up and the illuminating light travels through the subsequently fitted fibres with an energy loss. Constructions operating using this principle can be seen, among others, in U.S. Pat. No. 4,161,348 and registration number U.S. Pat. No. 3,854,792.

The disadvantage of the known solutions, however, is that although complex the relatively precise fitting of the optical fibres after they have been cut can be solved, as a consequence of which the security sealing device is not able to perform what is expected of it, as due to the partially restored optical light transmission the reduction of the intensity of the travelling light can only be shown with difficulty, on occasions with costly instruments, which, however, are not available in every case.

Monitoring direct light-transmission optical seals is made more difficult by that during the use of a cable bundle put together from several optical fibres over time some of the constituent fibres get damaged, cracked, as a consequence of which the intensity of the light from the illuminating light source is reduced. Due to this in the case the transmitted light intensity of optical fibre security sealing units is reduced it is difficult to decide whether the seal has lost some of its light-transmitting ability due to natural wear or as a consequence of intentional damage, breakage.

Another disadvantage is that in cases where long signalling units need to be used, e.g. fitting truck tarpaulins with security sealing devices, then the significant distance can cause problems during the inspection of the integrity of the sealing unit.

Our aim with the solution according to the invention was to overcome the deficiencies of the known optical fibre seals and to create a version that on the one hand makes it clearly determinable whether the sealing unit has been damaged or not during a simple inspection and, on the other hand, excludes the possibility of the sealing unit being restored to its original or similar condition after it has been damaged.

The basis of the invention idea was formed by the recognition that if the optical fibres suitable for transmitting light are divided into several groups, and the groups are fixed at the ends of the closing unit in a way that is not usual and arrange them inside the cable sheath in a new way, then the task can be solved.

In accordance with the set aim the optical fibre sealing unit according to the invention—which contains a basic bundle consisting of light-transmitting fibres, a signalling bundle also consisting of light-transmitting fibres, a cable sheath and receiving bodies positioned at both ends of the cable sheath, the receiving bodies have an accepting space suitable for the fixing of at least some of the light-transmitting fibres and a transmitting body that allows light to pass through it, the basic bundle and the signalling bundle are arranged in the cable sheath and the one end and the other end of the basic bundle are each fixed in the accepting space of a receiving body in such a way so that they can not move, one end of the basic bundle is fitted to the transmitting body of one of the receiving bodies and the other end of the basic bundle is fitted to the transmitting body of the other receiving body—is set up in such a way so that one end of the signalling bundle is fixed in the vicinity of the one end of the basic bundle so as to prevent light input, while the other end of the signalling bundle is clamped into the light-transmitting output member in the vicinity of the other end of the basic bundle.

A further criterion of the sealing unit according to the invention may be that the output member is built into the receiving body that fixes the other end of the basic bundle, and the other end of the signalling bundle is connected to the output member via the accepting space of the receiving body fixing the other end of the basic bundle.

In a possible construction of the sealing unit one end of the signalling bundle is contained in a light-proof cap.

In another version of the invention the one end of the signalling bundle is positioned in the accepting space of the receiving body that fixes one end of the basic bundle.

From the point of view of the sealing unit it may be favourable if it is coupled with a supplementary signalling bundle made up of light-transmitting fibres, one end of the supplementary signalling bundle is clamped into a light-transmitting output member fixed in the vicinity of one end of the basic bundle, while the other end of the supplementary signalling bundle is positioned in the vicinity of the other end of the basic bundle in such a way so as to prevent light input.

In a further realisation of the invention the one receiving body and the other receiving body have a closing member for fixing the locking body.

In a still different construction of the sealing unit the closing members are formed by closing apertures in the one receiving body and the other receiving body and guide sheaths surrounding the closing apertures. The guide sheaths are surrounded by the disordered light-transmitting fibres of the basic bundle and the signalling bundle and/or the supplementary signalling bundle.

In a still further different construction of the invention the transmitting body of the one receiving body and the transmitting member of the other receiving body, as well as the output member have optical lenses.

The sealing unit according to the invention has numerous advantageous characteristics. The most important of these is that due to the new light-transmitting fibre arrangement, grouping and fixing, in the case that the sealing unit is cut at any position the fibres of the basic bundle and the signalling bundle become absolutely and irrecoverably mixed up, and so during the cutting of the sealing unit, without using separate auxiliary devices or measurement instruments an attempt at unauthorised penetration can be simply, immediately and clearly observed, determined.

Another advantage is that due to the use of the signalling bundle, positioned in a modern way, the original condition can not be restored, in this way there is no way of covering up the traces after a “break in” by repairing the damaged elements of the sealing unit.

Another advantage is that in the case of a suitably set up basic bundle and signalling bundle the sealing device according to the invention contains several essentially independent security and check paths, in other words its protection and signalling ability exceeds that of the traditional lead seal type security sealing devices.

In the following we present the invention in detail in connection with examples on the basis of drawings. On the drawing

FIG. 1 shows a version of the sealing unit according to the invention in side view, in partial section,

FIG. 2 shows a detail of a cross section of the sealing unit according to FIG. 1 taken along the plane II-II,

FIG. 3 shows the outline of another possible set up of the sealing unit.

FIGS. 1 and 2 contain a possible construction form of the sealing unit 1 according to the invention. It can be seen that the sealing unit 1 contains the basic bundle 10 and signalling bundle 20 placed in a cable sheath 30 sealed with the receiving body 40 at the one end 31 and with the receiving body 50 at the other end 32 The basic bundle is an optical cable made up of light-transmitting fibres 13, while the signalling bundle 20 is an optical cable made up of light-transmitting fibres 23. The receiving body 40 has an accepting space 41 for receiving the light-transmitting fibres 13 forming the one end 11 of the basic bundle 10 as well as a transmitting body 42. In the present case the transmitting body 42 has an opening in the receiving body 40 that allows the passage of light into which here there is an optical lens 90 fixed. The optical lens 90 of the transmitting body is connected to the one end 11 of the light-transmitting fibres 13 that form the basic bundle 10, so in this way light gets into the one end 11 of the basic bundle 10 through the transmitting body 42.

Also in the accepting space 41 of the receiving body 40, it is practical if the one end 21 of the signalling bundle 20 is positioned embedded among the light-transmitting fibres 13 that form the basic bundle 10, which, however, is sealed in the light-proof cap 70. Due to the effect of the light-proof cap 70 light arriving from the external environment can not penetrate into the light-transmitting fibres 23 of the signalling bundle 20 via the one end 21 of the signalling bundle 20.

It can also be observed on FIG. 1 how the other end 12 of the basic bundle 10 and the other end 22 of the signalling bundle 20 is positioned in the accepting space 51 of the receiving body 50 positioned at the other end 32 of the cable sheath 30 of the sealing unit 1. The other end 12 of the light-transmitting fibres 13 forming the basic bundle 10 are connected to the optical lens 90 fitted into the transmitting body 52, which, in this way, makes it possible for the light ray running along the light-transmitting fibres 13 of the basic bundle 10 to escape from the sealing unit 1. Beside the transmitting body 52 the receiving body 50 also includes the output member 60, which also has an optical lens 90. The output member 60 is fixed to the other end 22 of the light-transmitting fibres 23 of the signalling bundle 20 in such a way so that the light-transmitting fibres 23 connect to the optical lens 90.

We have to mention here that the optical lenses 90 do not necessarily have to be independent components, a solution can be imagined where the one end 11 and the other end 12 of the light-transmitting fibres of the basic bundle and the other end 22 of the light-transmitting fibres 23 of the signalling bundle 20 are suitably clamped and ground to a form that suits the optical objective.

It can also be observed on FIG. 1 that in the present version of the sealing unit 1 the receiving body 40 and the receiving body 50 have closing members 3 for connecting the locking body 2. In the receiving body 40 the closing member 3 consists of a closing aperture 43 and a guide sheath 44 surrounding the closing aperture 43, while in the receiving body 50 it consists of a closing aperture 53—of a shape and form the same as the previous one—and a guide sheath 54 surrounding the closing aperture 53. FIG. 2 shows that the light-transmitting fibres 13 and the light-transmitting fibres 23 of the basic bundle 10 and the signalling bundle 20 of the sealing unit 1 in the accepting space 51 of the receiving body 50 completely surround the guide sheath 54 that completely delimits the closing aperture 53. The situation is the same with the guide sheath 44 of the closing member 3 belonging to the receiving body 40 of the sealing unit 1. We have to mention here, however, that the closing member 3 does not only have to be in the form and operate with the principle presented in FIGS. 1 and 2. Completely different solutions can also be imagined. In such a way such a construction form is possible in which the base of the external form of the receiving body 40 and receiving body 50, e.g. cone, pyramid or hammer serves as the closing member 3, and provides suitable closing in this way.

During the use of the sealing unit according to FIG. 1 the cable sheath 30 and naturally the receiving body 40 at the one end 31 of the cable sheath 30 has to be threaded through the fixing loops of the closing body of the area to be protected, e.g. tarpaulin or door, then the closing member 3 of the receiving body 40 and the closing member 3 of the receiving body 50 are placed next to each other and locked with the locking body 2. After the sealing unit has been fixed—in the case of a goods vehicle—the consignment can be started out.

At the destination the integrity of the sealing unit 1 can be determined by getting a light ray into the light-transmitting fibres 13 of the basic bundle 10 via the optical lens 90 belonging to the transmitting body 42 of one of the receiving bodies 40 of the sealing unit 1. If the basic bundle 10 is undamaged then the light rays get from one end 11 of the basic bundle 10 directly through the light-transmitting fibres 13 to the other end 12 of the basic bundle 10, and the optical lens 90 of the transmitting body 52 of the receiving body 50 holding the other end 12 of the basic bundle lights up, while the optical lens 90 of the output member 60 of the receiving body 50 remains dark, as light can not get into the light-transmitting fibres 23 of the signalling bundle in the cable sheath 30.

If, however, during transportation persons have tried to gain access to the protected area by cutting the sealing unit, when the sealing unit 1 is cut the disordered and mixed up light-transmitting fibres 13 and light-transmitting fibres 23 of the basic bundle 10 and the signalling bundle 20 touch each other when refitted so that some of the light-transmitting fibres 13 of the basic bundle 10 in the cross section of the cut meet the light-transmitting fibres 23 of the signalling bundle. In such a case during the inspection at the destination the light getting into the transmitting body 42 of the receiving body 40 of the sealing unit 1 is split up within the cable sheath 30 at the place of damage and continues so that a part of it gets to the transmitting body 52 of the other end 12 of the basic bundle 10, and the other part goes from the light-transmitting fibre 13 to the light-transmitting fibre 23 and continuing its path in the signalling bundle 20 it arrives at the output member 60 of the receiving body 50 and “illuminates” it. At this time the brightness of the transmitting body 52 goes down, and at the same time some of the light amount put in appears at the output member 60, which simply and reliably signals the fact of unauthorised penetration.

On FIG. 3 a sealing unit 1 can be seen in which in the space delimited by the cable sheath 30 one end 31 fixed to the receiving body 40 and the other end 32 fixed to the receiving body 50, beside the basic bundle 10 and the signalling bundle 20 there is a supplementary signalling bundle 80 that has the same task as the signalling bundle 20. The supplementary signalling bundle 80 is also an optical cable put together from light-transmitting fibres, which is practically exactly the same as the signalling bundle 20. One end 81 of the supplementary signalling bundle 80 is also closed with a light-proof cap 70, and its other end 82 also has an output member 60. In this construction form—similarly to that presented in FIG. 1—the one end 11 of the basic bundle 10 is connected to the transmitting body 42 of the receiving body 40, and the other end 12 of the basic bundle 10 to the transmitting body 52 of the receiving body 50, while the one end 21 of the signalling bundle 20 closed with a light-proof cap 70 is fitted to the receiving body 40 and the other end 22 of the signalling bundle 20 connected to the output member 60 is fitted to the receiving body 50. The one end 81 closed with a light-proof cap 70 of the supplementary signalling bundle 80 is fitted into the receiving body 40, and the output member 60 at the other end 82 of the supplementary signalling bundle 80 is fitted into the receiving unit 40 of the sealing unit 1.

In the case of this version at the destination the inspection can be carried out from both the receiving body 40 and the receiving body 50 of the sealing unit 1. In the case of sabotage on illuminating into the basic bundle 10 from the transmitting body 42 of the receiving body 40 the process presented in connection with FIG. 1 is carried out. But when light rays are put into the light-transmitting fibres 13 of the basic bundle 10 from the transmitting body 52 of the receiving body 50, then at the breakage point the light travelling in the light-transmitting fibres 13 of the basic bundle from the receiving body 50 towards the receiving body 40 goes over from the light-transmitting fibres 13 to the light-transmitting fibres 83 of the supplementary signalling bundle 80. The light going over into the light-transmitting fibres 83 on reaching the other end 82 fitted into the output member fixed in the receiving body 40 lights up the optical lens 90 at the other end 82 of the supplementary signalling bundle 80 and so the inspection is possible in the direction opposite to that presented in FIG. 1.

The invention can be used well in all areas where the movement of objects needs to be prevented, determined closed areas, e.g. the load areas of goods vehicles and valuables, goods and products placed in closed areas need to be protected from theft and penetration.

List of references

-   1 sealing unit -   2 locking body -   3 closing member -   10 basic bundle -   11 one end -   12 other end -   13 light-transmitting fibre -   20 signalling bundle -   21 one end -   22 other end -   23 light-transmitting fibre -   30 cable sheath -   31 one end -   32 other end -   40 receiving body -   41 accepting space -   42 transmitting body -   43 closing aperture -   44 guide sheath -   50 receiving body -   51 accepting space -   52 transmitting body -   53 closing aperture -   54 guide sheath -   60 output member -   70 light-proof cap -   80 supplementary signalling bundle -   81 one end -   82 other end -   83 light-transmitting fibre -   90 optical lens 

1. Optical fibre sealing unit which contains a basic bundle consisting of light-transmitting fibres, a signalling bundle also consisting of light-transmitting fibres, a cable sheath and receiving bodies positioned at both ends of the cable sheath, the receiving bodies have an accepting space suitable for the fixing of at least some of the light-transmitting fibres and a transmitting body that allows light to pass through it, the basic bundle and the signalling bundle are arranged in the cable sheath and the one end and the other end of the basic bundle are each fixed in the accepting space of a receiving body in such a way so that they can not move, one end of the basic bundle is fitted to the transmitting body of one of the receiving bodies and the other end of the basic bundle is fitted to the transmitting body of the other receiving body characterised by that, one end (21) of the signalling bundle (20) is fixed in the vicinity of the one end (11) of the basic bundle so as to prevent light input, while the other end (22) of the signalling bundle (20) is clamped into the light-transmitting output member (60) in the vicinity of the other end (12) of the basic bundle (10).
 2. Sealing unit according to claim 1, characterised by that, the output member (60) is built into the receiving body (50) that fixes the other end (12) of the basic bundle (10), and the other end (22) of the signalling bundle (20) is connected to the output member (60) via the accepting space (50) of the receiving body (50) fixing the other end (12) of the basic bundle (10).
 3. Sealing unit according to claim 1 or 2, characterised by that, one end (21) of the signalling bundle (20) is contained in a light-proof cap (70).
 4. Sealing unit according to any of claims 1-3, characterised by that, the one end (21) of the signalling bundle (20) is positioned in the accepting space (41) of the receiving body (40) that fixes one end (11) of the basic bundle (10).
 5. Sealing unit according to any of claims 1-4, characterised by that, it is coupled with a supplementary signalling bundle (80) made up of light-transmitting fibres (83), one end (81) of the supplementary signalling bundle (80) is clamped into a light-transmitting output member (60) fixed in the vicinity of one end (11) of the basic bundle (10), while the other end (82) of the supplementary signalling bundle (80) is positioned in the vicinity of the other end (12) of the basic bundle (10) in such a way so as to prevent light input.
 6. Sealing unit according to any of claims 1-5, characterised by that, the one receiving body (40) and the other receiving body (50) have a closing member (3) for fixing the locking body (2).
 7. Sealing unit according to claim 6, characterised by that, the closing members (3) are formed by closing apertures (43, 53) in the one receiving body (40) and the other receiving body (50) and guide sheaths (44, 54) surrounding the closing apertures (43, 53).
 8. Sealing unit according to claim 7, characterised by that, the guide sheaths (44, 54) are surrounded by the disordered light-transmitting fibres (13, 23, 83) of the basic bundle (10) and the signalling bundle (20) and/or the supplementary signalling bundle (80).
 9. Sealing unit according to any of claims 1-8, characterised by that, the transmitting body (42) of the one receiving body (40) and the transmitting member (52) of the other receiving body (50), as well as the output member (60) have optical lenses (90). 